RIVERSIDE, Calif -

Southern California Edison's decision today to permanently pull the plug on its San Onofre nuclear power plant is not expected to have much of an impact on Riverside Public Utilities customers, city officials said.

RPU has a 1.79 percent stake in the San Onofre facility, which complemented the city's renewable -- or "green" -- energy portfolio, but officials do not anticipate the loss of electrical supply from the Orange County plant would create disruptions.

"We do not believe this decision by SCE will have a significant impact on rates or our power supply," said RPU General Manager David Wright.

He noted that SCE did not give the city any advance notice of plans to permanently shutter the San Diego County seaside plant, which sits just off Interstate 5 near San Clemente. However, according to Wright, the city had been engaged in contingency planning in case the San Onofre units were retired.

San Diego Gas & Electric also have a small ownership stake in the plant.

Ted Craver, chairman and CEO of Edison International, SCE's corporate parent, cited uncertainty about when the two units at the plant, which were taken offline because of technical issues, would be allowed to restart. The company also said the administrative process to gain regulatory approval to restart could have lasted more than a year, entailing a cost too great to bear.

The plant's two reactor units, referred to as Unit 2 and Unit 3, have been offline since early 2012. Unit 1 was in operation from 1968 to 1992, when it was shut down over fears it could not withstand a major earthquake.

Unit 2 was taken out of service Jan. 9, 2012, for planned routine maintenance, while Unit 3 was shut down abruptly on Jan. 31, 2012, after a small leak of radioactive steam occurred. No one was hurt, but both reactors were kept offline while the issue was investigated.

Edison executives would later reveal the leak was caused by premature wearing of steam pressure tubes in the reactors.

Edison spent months trying to gain permission from the Nuclear Regulatory Commission to restart one unit at 70 percent power for five months as a test run.

Edison said today it would pursue damages from Mitsubishi Heavy Industries of Japan, the company that supplied the replacement steam generators that wore out sooner than expected.

At its peak, the plant supplied power to 1.4 million households that now receive energy from other sources via the grid, according to Edison.